Piston.



30 away from each other.

GRANVILLE E. STALLMAN, PHILADELPHIA, PENNSYLVANIA.

r'r's'ron.

To all whom it may concern:

Be it known that I, GRANVILLE H. STALL- MAN, a citizen of the United States, and a resident of the city and county of Philadelphia, State of Pennsylvania, have invented certain new and useful Improvements in Pistons, oia which the following is a specification.

My invention relates to improvements in pistons, and more particularly to improvements in the single-acting, self-adjusting,

rodless pistons used in sausage stuiiing ma- K chinos, the object of iny invention being to furnish a piston for this purpose, to be operated by compressed air preferably, the

l5 packing oi which will on the operative stroke be expanded to make a perfectly air or liquid tight joint with tliecylinder and on the return stroke, or as soon as the actuating pressure is relieved, will contract and permit a 'free vfalling of the piston.

In the drawings, Figure 1 is a central sectional elevation of part of a cylinder fitted with my improved piston, .and Fig. 2, a section of Fig. 1 on line A-A.

a is a cylinder furnished at the lower end with an air or liquid entrance and exhaust b.

c is the piston which is made in two parts, a -niain part d, and a top part e, which are, by 4means of a bolt f, adjustable towards or formed inthe eriphery of the piston is a packing 7L wliic is adapted to engage the cylinder a. Immediately back of this packing is an elastic packing i, preferabl constructed of rubber, which has a c annel shape and in which is -placed a ring j which acts to keep the packing "i in shape and A,which is furnished with perforations c which .connect with passages Z in the main part d of 40 the piston, these passages being open to' the air or liquid in the cylinder a.

When air or liquid is admitted to the bottom of the cylinder a it acts against the bottom of the piston c to lift it and atl the same time it enters the passage, or passages l and presses against the inner side of the elastic packing i and forces this packing outwards causingthe packing k to bear tightly against the walls of the piston.

Thearea'of the bearing surface 'ofy the packing hiagainst the cylinder is so large as :to effectually -prevent any leakage ast lit during the operation oi4 the piston'. ssoon as the actuating pressure in the cylinder a vbeneath the piston is relieved the pressure Specication of Letters Patent.

Application led November .8, 190.7. Serial No. 401,214.

Placed in a recess g Patented Aug. 25, 1908.

forcing the packing h outward is withdrawn, the packings collapse, and the weight of the piston c will cause it to drop to the bottom of the cylinder.

My device obviates the ossibility of the piston sticking to the cy inder when the pressure in the latter is relieved.

The packings can be adjusted in relation to the cylinder by setting the part e of the piston towards or away from the part d. VIi

it be set closer it will compress the rubber ring i edgewise and will cause it to force the packing h outward. If it be set away the opposite will occur.

In order to provide against the possibility of the passage Z not iiioshiiig with the opcnj ing 7c in the ring y, I furnish the part d of the piston with a groove 1n which engages or j opens into the passage or passagesl and in case of the ring being set far down by adj usting the part c of the piston tightly against the part d, would direct the air from the assage l to the opening 7c.

aving thus described my invention I claim as new and desire to secure by Letters Patent 1. In a piston, in combination, a main part and a top part and means for adjusting said )arts tow ard or away from one another, an e astio packing seated in an annular groove in the periphery of the piston and engaged at its ends by the main and top portions of said piston, saidannular groove; a packing surrounding the outer face of said elasticv packing adapted to engage the cylinder in which said piston works, and a connection leading from the pressure end of said piston to the rear of said elastic packing.

2. In a piston, in combination, a main part and a top part and means for adjusting said i top portions thereof, said annular groove; av

perforated annular ring in the channel of said elastic packing, a packing surrounding the outer face of said elastic packinggand a .connection leading from the pressure end of said piston to the perforation insaidring.

GRANVILLE n.sTALLMAN. j

` Witnesses: l

GEORGE W. SELTzER, CHARLES A. RUTTER. 

